The trick is - guess what? - to pick a category then a subset of that.
Building the ecommerce chain is easy with the popular route being Shopify (website), Oberlo (source and your site integrator) and AliExpress for the suppliers. Shopify offers a two-week free trial and I found it to be simple to use and excellent overall. Just I didn't take the plunge in paying for the service.
After research, read countless articles, and watched hours of vids on YouTube. Then I went off and had a look around for what I wanted to sell. Nothing electronic, mechanical, or with a battery inside; I just didn't want the hassle of handling returns, arranging for replacement parts and all that.
There were three other factors guiding my product hunt.
1) Nothing plastic
2) Must have free shipping to the UK and USA
3) Must be available in sets not as individual products
4) Must have many colours and sizes
I found what I wanted to sell. I found the suppliers on AliExpress and filtered for free shipping. Checked how many orders they'd taken in the last three years. Then I went shopping for a URL.
Even this took longer than expected. I needed a .com for the US and a .co.uk for the UK. Because voice search is becoming increasingly popular, I wanted a URL that would be something people would both ask and type. Found that after a considerable amount of time and effort.
Part 2 - coming soon